Production of motor fuel



. alkylated benzenes by lar unsaturated material, either from the prod-Patented May 20, 1941 PRODUCTION OF MOTOR. FUEL Alexander N. Sachanenand Arlie A. OKelly, Woodbury, N. J., assignors to Socony-Vacuum OilCompany, Incorporated, New York, N. Y., a I

corporation of New York Nb Drawing. Application August 27,

Serial No. 227,106

4 Claims. (01. 260-671) This invention relates to the production ofalkyl aromatic'compounds by reacting aromatic and oleflnic hydrocarbons.J More particularly,

the invention relates to a process for the production of alkyl aromatichydrocarbons of high anti-knock value which are of suitable boilingrange for use as motor fuels.

Processes for the cracking lar petroleum fractions to gasoline result inthe production of hydrocarbons boiling within the gasoline range, andalso result .in the production of a considerable amount of lighter,normally of gas oil and simi- I gaseous hydrocarbon products.Appreciable quantitles of these lighter gaseous products are olefinicand unsaturated in nature. Appreciable quantities of thegasoline-likecondensate are also oleflnic in nature. Processes of this nature resultin the production of gasolines of varying qualities with respect toanti-knock characteristics, dependent upon both the charging stockprocess of cracking through which it has been passed.

Many of the liquid gasoline-like products of such cracking processes arerelatively high in anti-knock characteristics when judged from thestandpoint of the requirements of an automobile motor. Few of them,however, even approach the possession or sufliciently highanti-knockcharacteristics to permit of their use, as produced, in

more advanced high compression type of engines, as for example theengines designed for use in aviation.

originally processed and upon the nature of the Alkylated benzenesboiling within the boiling 7 range of commercial gasoline are known tobe capable, when mixed with gasoline, of imparting to the mixture 2.high degree ofanti-knock capability. Various methods for the productionof combining olefinic O'r simiuctsof. a conventional cracking process orfrom other sources, with aromatic-compounds of the benzene or itshomologues have'been nature of proposed.

The proposed prior processes, in general, take produced during cracking;together with benzene, through condensing catalysts of the nature ofiullers earth, at these low temperatures. However, at such lowtemperatures clay-like catalysts do not appear to exert much, it any,catalytic action, and, as the reaction does not proceed appreciably atthese low temperatures without the use of a catalyst, other catalysts,such as sulfuric acid; etc. are'generally used. s

In general, the catalytic processes conducted at low temperatures areopen to many objections. One of the principal disadvantages of suchprocesses when employing the usual low-temperature reactive catalysts,such as metal chlorides, sulfuric acid and phosphoric acid, is that theconsumption of catalytic material is relatively high, and, if notentirely consumed, a complicated and costly process of regeneration isrequired. 'Many of these catalytic materials are corrosive to thematerials of construction normally used, and introduce this, as well asother operating difilculties.

A more serious objection, however, to processes carried out at lowtemperatures for the alkylation of aromatic compounds to form compoundsto be added to gasoline, isthat of low yield of products distilling inthe boiling range of gasolines.- The low yield is caused-in the main, bya considerable amount-of the raw materials forming compounds of higherboiling range which are not usable in gasoline, and'are particularlyunsuitable for'usejn gasolines of the lower boilingpoint type, such'asgasolines of aviation grade and the like. Since any condensationcatalyst will not only bring about the joining of a single alkyl radicalwith an aromatic radicaL'but will also, more or less,efiect-polymerization reactions among the alkyl radicals themselves,aswell as the condensation of several alkyl radicals with a singlearomatic radical, it may be seen that the possibilities of loss of yieldfrom this source-may be quite high.

the nature of catalytic condensation reactions.

carried out at'comparativ ely. low temperatures in the presence ofcondensation catalysts. For example, such catalysts as aluminumchloride, various other metallic chlorides,sulfuric acid, phosphoricacid, and the like, peratures, i. e. temperatures or the nature of 30 to350 F. (about --1' O. to +1'7'7 0.). It has also been proposed to passcracked gasoline in company with the normally gaseous materials 0are'used at low tem- It is. an object of this invention to provide ahighly efllcient process for the production of alkyl aromatic compounds.a

Another object otthis invention is to provide a highlyeflicientprocessfor. the production of alkylated aromatic compoundswhichpossess a high anti-knock value and are of suitable boiling rangeto be used in motor fuels.

A further object of this invention is to provide a highly efficientprocess-fol the production of alkylated aromatic compounds which afiordsop-- timumconditions for the-formation of alkylated aromatic compoundsof a desired boiling range and minimizes the formation of alkylatedbenzenes without the desired boiling rangeand, furthermore, acts toreduce compounds of undesired boiling range, if formed, to compounds thedesired boiling range. I Still another'object of this invention is toprovide a process for the production of alkylated aromatic compoundswherein such catalysts as various clays and the like may be used with ahigh degree of success. This invention is based upon the discover thatthe reactions between unsaturated or olefinic materials and aromaticmaterials to produce compounds of the alkylfbenzene type which arewithin the gasoline boiling range are remarkably improved and, moreover,give commercially feasible yields even in cases where no perceivablereaction .occurs under more moderate conditions of operation, when thereactions are-carried out at high temperatures of the nature hereindisclosed and under suitable conditions tending to promote thecondensation reaction. For v.instance, we have discovered that when thereaction is carried out at temperatures upwards of about 400 C.,catalytic materials promote the reaction to an unusual degree and underoptimum conditions as when elevated pressures are also used, practicallya theoretical yield of aralkyl compounds within the gasoline boilingrange. may be obtained.

It is believed that the remarkably improved results derived from ourinvention are attributable to the fact, that at the elevatedtemperatures of .our process combined with the action of a suitablecatalyst, not only will olefinic or similar compounds combine witharomatic materials to form alkylated aromatic compounds within thegasoline boiling range to an optimum degree, but

that also under these conditions the formation 'of polymers of olefinicmaterials and of polyalkyl benzenes not within the gasoline boilingrange is minimized and that such compounds, if formed, are immediatelybroken down into lower boiling compounds of an-alkylated benzene naturewhich are within the gasoline boiling range,

The aromatic compounds with which our invention is concerned are of thenature of henzene', its homologues or compounds containing benzenenuclei. The aromatic compound (or mixture of aromatic compounds) maybeemployed in a relatively pure condition or they may be supplied by theuse of products which are -known to contain asubstantial portion ofthese aromatic ingredients. Likewise the olefinic materials may besupplied as a relatively pure product or may be derived from the use ofa product containing a substantial amount thereof. For

instance tthe olefinic material may be propylene, butylene, amylene,mixtures thereof, normally gaseous products of cracking, crackedgasolines or fractions .of cracked gasolines containing ole- Thecatalyst employed should be highly selective in that it promotesalkylation reactions but is either a non-catalyst or a negative catalystfor other reactions. Catalysts usually, do not act with perfectselectivity, hence normally one must choose a catalyst which actspredominantly in the desired manner. The catalysts which we prefer touse are of the clay type. In addition to the various clays themselvesand the various activated clays, there are numerous other porous,

refractory, adsorptive materials of similar nature which may be used andcome under the common designation of clay type catalyst, for example,

earth. Furthermore, it is to be understoodthat these various clay-typecatalysts which have other catalytic materials impregnated therein orthereon or otherwise conjoined for use maybe employed. In general, anyalkylation catalyst which is active at the temperature of our reactionmay be used. However, it is to benoted that the normally used catalystsof low temperature processes, such as aluminum chloride, sulfuric acid,etc. cannot be used in our high temperature process. 1

Since the alkylation reaction, together with the attendant crackingreactions which are present at the temperatures herein disclosed, bringabout a gradual poisoning or deterioration of the catalyst by thedeposit of carbon and carbonaceous impurities thereon, it is well to usea clay which I is possessed of a sufficiently refractory nature so thatit may be regenerated in situ by burning; in fact, some of the claycatalysts used by us have been regenerated as manyas 8000 times and arestill quite satisfactory. Because of the ease with which the clay-typecatalysts may be regenerated, they afford a substantial advantage intheir use. It is also well to use clay particles of such physical naturewith respect to size and dimension that they may be effectively packedtogether in a catalytic mass and yet, at the same time, present asuflicient cross-sectional area of flow that the reactants may have aready passage therethrough as well as a suitable exposure of catalyticmaterial to reactants. A convenient and efficient form for the catalystis small granules, rods or cylinders.

. The use of clay-type catalysts has many distinct advantages inaddition to those already named. For instance, the clay is not corrosiveto the normal apparatus as are the usual-alkylation catalysts and,furthermore, there is a relatively small consumption of the claycatalyst during operation as contrasted to the relatively highconsumption of catalyst which is usually encountered. It is to be notedthat our process alone appears to afford suitable conditions for thesatisfactory use of clay catalyst since under more moderate conditions ofoperation the clay' appears to be relatively ineffective as a catalyst.

The temperatures employed in our process should be-sufiiciently high tobe capable'of pro ducing at least a partial cracking of the hydrocarbonshaving boiling points higher than thegasoline boiling range, as, forinstance, temperatures upwards of about 400 C., and it is desirable tomaintain the temperature between about 400 C. and 600 C., since above600 C. the reof pressures between about 50 and about atmospheres. It isto be'understo'od, however, that pressures above 100 atmospheres and upto about 250 atmospheresmay likewise be used with good results; Above250 atmospheres the results become less favorable as there is anincrease in the production of heavy molecules above the at a reaction"temperature of 890 F. (about 470 C.) for a time of fifteen minutes.

At atmospheric pressure and in the absence or a catalyst, no reactionproducts of the nature of alkylated benzenes were detectable in theeflluent.

At atmospheric pressure in the presence of a highly activated porousad'sorptive catalyst or the clay type, reaction products'indicated that45% of the theoretical yield of alkylated benzene products could beobtained. I

At a pressure of 1500 pounds per square inch with the catalyst, areaction yield of 58% of the theoretical was obtained.

At a lower temperature'range of 400-to 600 F. (about 205 to 315 'C.which is much higher than the customary alkylating temperature) even inthe presence of a highly active catalyst of the clap type, no measurablerate of reaction was found.

To further point out the diflerences between the prior art and thepresent invention, we may discuss the reactions involved. For example,when benzol is condensed with amylene, the fol lowing reaction takesplace:

cerreq-campc rn-csmr and with butylene: v

CeHc-FC4Ha=CeH5'-C4H9 These are the simplest reactions possible underthese circumstances, and, as may be observed, result in each case in thealteration of benzol.

' which has a boiling point of 194 F. (within the kylated aromatics ofconsiderably higher boiling ranges nottcapable of being used in any typeof gasoline.

In contrast,. the reaction of benzene with .amylene and butylene at thehigh temperatures of our process hereindescribed are-mainly of thefollowing nature: I--With amylene:

These two compounds formed, namely propyland ethyl-benzene, boilrespectively at 310 F. and 284 F. and both may be used even in thelow-boiling typesof gasoline, such as aviation gasoline. Thesedifferences in the type of reaction encountered are especially strikingwhen the material from which the alkylaiting compounds are derived isgasoline or a mixture of gasoline and cracking vapors, because many ofthe oleflnes present, particularly those derived from the gasoline, arehigh molecular weight olefines, and many of them are oleflnes of acomplicated-nature quite prone to-polymerization, as is evidenced bytheir /capability of gum formation, and the like, and by their abilityto polymerize to materials of boiling point higher than gasoline underthe relatively simple treatment encountered in the vapor phasedegummingprocesses in contact with fullers earth.

With increases in temperature this difference in the type of reactionbecomes more striking,

since with increases in temperature. there is a rapidly increasingtendency to' break up the aliphatic radical, resulting in the productionof alkylated benzenes containing very short and simple alkyl radicals,such as toluene, ethyl benzenes and propyl benzene and, consequently,re-

sulting not only in the production of a greater amount of alkylatedbenzenes within the boiling range of aviation gasoline, but also in amuch more eflicient utilization of the aromatic radicals present.

The-1 process may be carried out either asa batch operation or theprocess may be made continuous by employing a pipe still and a reactionchamber.

The effectiveness of this method of operation, and the eifect of the.several variables, may be seen from a consideration of the followingexamples, in each of which one or more of the operating principlesherein disclosed is applied. It is to be understood that these examplesare merely for purposes of illustration and notto be.

construed as limiting the invention in any sense.

Example I I Example II Toluene is alkylated wRh amylene by passing themixture over a, similar-activated clay catal st at a temperature of 885F. (about- 474 C.) a d at a pressure which is substantially atmospheric(batch operation). The total yield of alkylated toluenes is 57% of thatwhich might theoretically be expected, and of these alkylated toluenesare within the gasoline boiling range.

Example III Benzene is alkylated with butylene in the presence of asimilar activated clay catalyst ata temperature of 850 F..(ab out 454C.) at a pressure of 1500 pounds per square inch gauge (100 atmos.) foraperiod of fifteen minutes (batch operation). The total yield ofalkylated benzenes is 74% of that which might be expected, and of thesealkylated benzenes over arewithin the gasoline boiling range.

Example IV ene and 17% butylenes in the presence of a clay The abovemixture of lihuefled gases' and an excess of benzene is charged to thepipe catalyst.

still at 975 F. under a pressure of 1500 lbs. per square inch gauge inaonce-through process. The total yield of alkylated benzenes is 96% ofthat which might be expected, and of these pounds inthe gasoline boilingrange which comprises alkylating aromatic hydrocarbons with .olefinehydrocarbons at a, temperature, between about 400 C. and about 600 C. inthe presence of a catalyst comprising an association oi. silicon oxideand aluminum oxide and under 'a superatmospheric pressure. e

2. A process of preparing alkyl aromatic compounds in the gasolineboiling range which comprises alkylating aromatics with olefines' at atemperature between about 400 C. and about 600 C. in the presence of aclay catalyst.

3. A proces of preparing alkyl aromatic compounds in the gasolineboiling range which comprises alkylating aromatics with oleflnes at atemperature between about 400 C. and about 60050. in the presence of aclay catalyst and under a pressure between about and about 250atmospheres. v

4. A process of preparing alkyl aromatic compounds in the gasolineboiling range which comprises alkylating aromatics with olefines 'at atemperature between about 400 C. and about 500 C. in the presence of aclay catalyst and under a pressure betweenabout 50 and aboutatmospheres.

r1. SACHAN'EN. ARLIE A. o'KEL r.

